Universal Shift Register

Discussion in 'Homework Help' started by iwanna4get, Feb 13, 2013.

  1. iwanna4get

    Thread Starter New Member

    Feb 13, 2013
    2
    0
    Ok we have Three Homework to make.

    To make applications of
    1.) Ripple Counter
    2.) Johnson Counter
    3.) Universal Shift Register

    So in order to make application of said experiments I have to study them so I did.

    I understood Ripple Counter and Johnson Counter, but I don't understand Universal Shift Registers.



    This is the circuit.
    [​IMG]


    I understand the table and what I don't understand is ;

    1.) What is the serial input for shift-right and serial input for shift- left is for?
    2.) How does it affect the circuit?
    3.) How come only there only seems to be 1 set of 4-bit input in the mux(where is the other selection of 4-bit input)?
    4.) When it shifts to the left or right does it continously shift until all output is zero (example: input is 0101 ; Sequence : 0011 , 0110, 1100 , 1000, 0000) or does it loop (example: input is 0101 ; Sequence : 0011 , 0110, 1100 , 1001, ... and so on)
    5.) How does it shift serial input?
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    1.)The serial input is so that you can shift data into the shift register. This is what makes it a universal shift register; it can shift in either direction, do parallel input & parallel output
    2.)It allows serial data to be put into the registers
    3.):confused: I don't know what you are trying to say here.

    If you are asking why there is one set of 4-bit inputs, why would there be more? these inputs are a parallel load, allowing the shift register to be loaded with a 4-bit value which would, most likely, be shifted out of the register.
    4. & 5.) You tell me. Is this not Homework Help? Go through the same sequence you suggested. make s1 = 1 and s0 = 0. put your values in and fill out a table representing the outputs. You must learn to trace the logic and determine the states of the device.

    As a side note, you are asking about whether the shift register does a shift(does not wrap data back into itself) and rotating(wraps data back into itself).
     
  3. iwanna4get

    Thread Starter New Member

    Feb 13, 2013
    2
    0

    What I meant is the 4x1 mux itself. with the number 0 1 2 3.

    But I am a complete idiot -.- .

    I mixed up the input and output ~ Gah

    Thanks about for answering number 2 I thought it was connected to S1 and S0 :D
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    No. You are not a complete idiot. Even if you don't believe that, it's important to understand that you can grasp concepts others would faint simply thinking about:) Have a little more confidence!

    Actually, I've never seen it done this way, so it took me a minute to understand its operation....
     
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